The data set includes the eddy flux observations from January 1, 2008 to December 29, 2010. The site is located in Xinchengzi Town, Miyun County, Beijing, with orchards (plum trees and apple trees), corn / bare land and towns under the surface. The longitude and latitude of the observation point are 117.3233e, 40.6308n, and the altitude is 350m.
The observation data released by the eddy correlator include: date / time, wind direction WDIR (?), horizontal wind speed wnd (M / s), standard deviation of lateral wind speed STD uuy (M / s), ultrasonic virtual temperature TV (℃), water vapor density H2O (g / m3), carbon dioxide concentration CO2 (mg / m3), friction velocity ustar (M / s), obkhov length, sensible heat flux HS (w / m2), latent heat flux Le (w / m2) ）, carbon dioxide flux FC (mg / (M2S)), quality mark of sensible heat flux QA ﹣ HS, quality mark of latent heat flux QA ﹣ Le, quality mark of carbon dioxide flux QA ﹣ FC. (76 & lt; Δ st & lt; 100, ITC & lt; 100); 7: (Δ st & lt; 250, ITC & lt; 250; 8: (Δ st & lt; 1000, ITC & lt; 1000); the rest is 9). The meaning of data time, for example, 0:30 represents the average of 0:00-0:30; data is stored in *. XLS format.
For observation test or station information, please refer to Jia et al. (2012), and for data processing, please refer to Liu et al. (2013).
The acquisition frequency of the eddy correlator is 10Hz, the frame height is 26.66m, the ultrasonic direction is due north, and the distance between the ultrasonic anemometer and the CO2 / H2O analyzer is 25cm.
The published data is the 30 minute data obtained from the post-processing of the original 10 Hz data collected by the edire software. The main processing steps include: outlier elimination, delay time correction, coordinate rotation (plane fitting), frequency response correction, ultrasonic virtual temperature correction and density (WPL) correction, etc.
The quality evaluation of each flux value is mainly the test of atmospheric stability (Δ st) and turbulence similarity (ITC). The 30min flux value output by edire software was also screened: (1) data in case of instrument error; (2) data in 1H before and after precipitation; (3) data with loss rate greater than 3% in every 30min of 10Hz original data; (4) observation data with weak turbulence at night (U * less than 0.1M / s). The average period of observation data is 30 minutes, 48 data in a day, and the missing data is marked as - 6999.
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